The proposed research on fibrinolytic enzymes in normal and malignant human gynecologic tissues is motivated by four concepts: 1) these enzymes, their activators and inhibitors may be important mediators of steroidal effects on normal functions, e.g., menstruation, ovulation, implantation, embryogenesis and pregnancy maintenance; 2) synthesis and secretion of high levels of plasminogen activators (PAs) may facilitate the growth, invasiveness and metastasis of ovarian and uterine cancers; 3) inhibition fo PA activity by progestins or glucocorticoids may contribute to their utility in cnacer therapy; 4) steroid-resistant tumor growth may reflect constitutive rather than controlled production of activators or loss of inducibility of inhibitors. Experiments on benign and malignant uterine and ovarian specimens will include: 1) quantitation and evaluation of the size, shape and charge of receptors for progestins and other steroids, under conditions recently found to stabilize other receptors, e.g., in molybdate-containing buffers, and 2) quantitation of PAs in tissue extracts, by fibrin plate assays with 125I- or fluorescein-labeled fibrin, or fluorometric assays using peptides containing arginyl- or lysyl-aminomethylcoumarin. Since two types of tissue PAs differ in size, substrate specificity, immunologic properties and steroid-responsiveness, we will adapt published methods to purify and prepare antibodies to both types: the major forms in normal urine (urokinase) and uteri. These immunologic reagents and gel electrophoresis will be used to classify the enzymes extracted from malignant gynecologic tissues or produced by explants in various hormonal environments. Organ cultures and stable cell lines derived from ovarian and uterine carcinomas will be used to investigate the molecular mechanisms of hormone action. For example, progestational inhibition of PA activity may reflect inhibition of enzyme synthesis, acceleration of its inactivation, or induction of inhibitors. Effects of progestins will be compared with those of anti-estrogens, which presumably function via estrogen receptors. Correlated studies of PAs and steroid receptors may reveal whether hormone-resistant enzyme production reflects quantitative or structural receptor defects, and whether PAs contribute to receptor cleavage in vitro. Eventual clinical applications may include the development of radioimmunoassays for PAs that may facilitate early detection of malignancy, selection of patients for endocrine therapy, and monitoring therapeutic responses.